Actually, the Second Amendment is about Militias, and combined with the Third Amendment (whose intent has been lost by a militarized police) was meant to define the use and purpose of militias. It had nothing to do with gun ownership, which was RARE in colonial America.
We already lock up 2 million people when most other industrialized nations lock up less than 100K. If locking people up solved crime, we'd be there already. If anything, the prison industrial complex makes things worse by creating an institutionalized criminal class.
Here's the problem with that thinking. The first is, I don't really want the government monitoring on line speech and deciding what is "unacceptable".
Secondly, since most of us post under fake names, how is the government supposed to know who Kyrz or JoeB131 really is when we say something "unacceptable".
Third, the people who are really planning something awful don't post it on line. Yes, THIS idiot did. Most mass shooters don't.
Again, all Stop and Frisk did was allow racist cops to hassle people of color. They weren't stopping and frisking white people.